Cord circuit



Nov. 27, 1928.

R. F. GOULD CORD CIRCUIT Inventor E'n F Bauld.

Nov. 27, 1928. 1,693,029

R. F. GOULD CORD CIRCUI T Filed March 25, 1927 2 Sheets-Sheet 2 Imren 01j Eu F Gould. m m-1 Patented Nov. 27, 192 8.

nuirrasmrss ROY F. GOULD, OF

CHICAGO, ILLINOIS, ASSIGHOR, TO RESERVE HOLDING COIvIPtzI-TY, OF

KANSAS CITY, MISSOURI, A CORPORATION OF DELAW'ARE.

com) cinema;

Application filed March 23, 1927. Serial No. 177,548.

The present invention relates in general to cord circuits for telephonesystems, but is particularly concerned with the provision of cordcircuit which is suitable for use in handling incoming calls from anautomatic exchange when connections are desired with subscribers of acommon battery exchange of the type in which a source of current ispermanently connected to the subscribers lines One object of theinvention s to prov de a cord circuit wherein the operator has herheadset automatically connected in bridge of the incoming trunk whentheanswering plug is inserted in the answering jack, and wherein herheadset is automatically disconnected and ringing automatically takesplace the instant the calling plug is inserted in the ack' the desiredline. Another object is to provide a peculiar ringing arrangementnecessary due to the peculiar type of manual equipment used, and

in the provision of a novel circuit arrange ment for cutting off theringing current as a result of the response of the called subscriber.

A further feature has to do with an arrangement in the cordfor causing areversing relay in the repeater of the incoming trunk to be actuated forthe purpose of operating a suhscribefis meter or for supervision.

Other features of the invention not specifically mentioned will becomeapparent from the detailed description and claims which follo-w. 3

In order to assist in describing the invention the same has beenillustrated in set of drawings comprising Figs. 1' and 2, which, whenplaced together with their correspondlines in alignment, show sufficientof a e vention to be t lephone system to enable the in exp i'ained andunderstood.

of the usual type used inautomatic telephone systems, while the oneshown in Fig. 2 is of the type commonly used in common battery manualsystems. I

The circuits of automatic switches available to the substation A.have'not' been shown, as switches of this character are well known andhave no particular bearing on the invention.

'lwoautomatic switches C and D, respectively, have been represented bythe dotted rec angles which indicate a line switch in which the callingline terminates and which,

The substation circuit shown in Fig. l is in turn, has access to aselector group as is customary.

The repeater E is of the general type ordinarily used in trunksextending between automatic and manual exchanges and is providedprimarily. to avoid the necessity of extending three conductors betweenthe two exchanges. This circuit has been slightly modified and will bedescribed in detail later. In F 2 is shown t-heanswering jack of thetrunk extending to zthe repeater E which is typical of answeringequipn'ient ordinarily used for this purpose. a

The cord circuit 0 is for use in answering calls originating in theautomatic exchange and for completing calls to the subscribers of.the'manual exchange. This cord circuit previously stated, has quite anumber of features of novelty all of. which will be describedhereinafter.

The answering jack J and its associated relay group is of the type usedin a common battery manual telephone system, developed by the EricksonCompany ofSweden and installed in the U nion of South Africa.

The various circuits and apparatus used having been generally describedthe invention will now be explained by giving a detailed accountof thecircuit operations wh ch takes place consequent to-theestablishment' ofa connection from the substation A of the automatic exchange to thesubstation B of the manual exchange.

The subscriber at substation'A upon desire,

ingto extend a connection to the substation B of the manual exchangeremoves his receiver, responsive to whichthe lineswitch' G, in the Wellknown manner, extends the line to a first selector, indicated at D. Thecalling sub scriber thereupon operates is calling device to position theswitch D opposite a level of bank contacts in which terminate trunkmultiples connectedwith the manual exchange.

In the present instance we will assume that connection is extended tothe repeater E.

I Responsive to the seizure of this repeater the line relay 17 energizesand at its armature 14F connect the trunk conductor 26 ,to the windingof relay 24 and ground, and at its armature 10 causes the energizationof holding relay 18. The relay 18 upon operating,

its arn'iature 19 disconnects the trunk conductor 25 from the winding ofrelay 23 and latter-y and connects conductor 25 to winding the releaseof the lineswitch C and the selector D, and atits armature 21 preparesan operating circuit for the slow release relay 22.

As soon as the Windingof relay 2% is connected to conductor 26, itenergizes in series with the relay Connected to the ring terminal of thejack J. The relay 2 operates and completes a circuit for slow releaserelay 23 Which in turn operates for a purpose Which will later be madeclear. operating, causes the lamp L to light and to informthe operatorof the incoming call.

The operator responds by inserting the plug l? of the cord into the jackJ thereby openingthe circuit of relay 70- and extinguishing thecalling'lamp L". The insertion of the plug l? into the jack J alsocauses the battery supply for 1 24 in the repeater to be transferred toth relay via the lower left-hand Winding of the repeating coil R, andring conductor 28. The relay 80 operates, at its armature l1 disconnectsthe release supervisory lamp L of the cord from the grounded sleeveconductor 29, and at its armature a2 and its Working contact closes apoint in the outgoing branch of the cord. As soon as the plug P isinserted in the jack J a circuit is also completed for the operatorsheadset cuton relay 40,.r'rom battery, Winding of relay {L0, armature 58and its restin contact, armature g l'and its resting contact, to thesleeve of the plug and jack to ground. The relay 40, therefore, operatesand at its armatures l3 and ll connects the operators headset across theright-hand windings of the repeating coil. B so that the operator mayinquireand obtain from the calling party the number of the de siredparty.

Since it scriber at substation B is desired the operator Will proceed totest the line to determine Whether the same is busy or idle. This isdone in the usual manner, by the operator touching the tip of her plugto the sleeve of the jack. .VVe Will. assume that the desired station isidle and therefore thatthe operator proceeds by inserting the plug 1?into the jack J. Responsive to this operation the relays 47 and 67operate. Relay 47 at its armatures 51 and 52 and their Working contactsconnects interrupted battery and interrupted ground, respectively, outover the tip and ring sides of the cord; in this manner although theindings 68 and 69 used for 'leeding current to the substation B arepermanently connected to the'line conductors, they do not interfere.

ith the transmisison oi ringing current. Interrupted battery, orinterrupted gcnerator, as indicated on the drawing, F 2, is meant to,designate rin ig current superinr posed on battery current and appliedintermittently, in conformance to the usual prac- T he relay 70 upon hasbeen assumed that'the sub During the ringing operation a small amount ofthe ringing current leaks back to the calling line through the condenser53 to inform the calling subscriber that the called The relay H at its.7

line is being signalled. armature 4l8'and its grounded Working contactcompletes a circuit for the supervisory at this time. Relay 55 at itsarmature 58' opensa point in the circuit of relay 40 causing I thisrelay to restore and to disconnect the operators head. set, and at itsarmature 57 prepares a point in the operating circuit of relay Shouldthe calling subscriber replace his receiver'ivithout having obtained theresponse of the called subscriber, line relay 1'? will re store and atits armature l l'break the circuit oi supervisory relay 30. This latterre-' lay upon restoring, at its armature 41 closes circuit for lamp L togive the operator disconnectsupervision and at its armature 42disconnects the interrupted generator so that signalling of the calledline is immediately discontinued.

We will assume that the called subscriber responds. While ringingcurrent is actually being transmitted out over the line the Winding ofrelay 68 is shunted. Accordingly, the removal oi the receiver at thecalled station will be Without effect until a silent period occurs. Assoon, however, as the ringing current is interrupted momentarily,providedthe called party at substation B has removedthe receiver,linerelay 68 energizes and connects batteryby Way oi? its Working contactand armature, armature and Working contact of relay 6'? directto thislatter relay, thereby short circuiting relay L, causing it to re store,to cut-oil the ringing current. This relay also at its armature a8 opensthe circuit of the lamp L to notify the operator that the calledsubscriber has responded; at its arn'iature 50 breaks the circuit ofslow release relay 55 and at therestingcontact of this armaturemomentarily completes a circuit, via Working contact and armature 57,for the relay 35. This latter relay upon operating, at'its armatures 36and 39 opens points in the interrupted ground and interrupted generatorringing circuit so tl at the subsequent energization of the ringingrelay 4:7 will be ineiicctive to again transmit ringing current to thecalled line, and atthc working contacts oil ari'natures 36 and 39connects the tip and ring conductors GOaiTd 61 to the right handwindings of the repeating coil. This relay also at its armature 39 andits orking contact connects relay 32 to the outgoing ring conductor 61of the cord which has battery supplied to it through the Winding 69.Relay 32, therefore, operates and .at its armature 33 looks up relay .35independent of relay 55. The relay 35 also, at its armature 38 opens thecircuit used .during the ringing operation to inform the callingsubscriber that the called subsoriber was being signalled, and at itsarmature 37 closes an operating. circuit for relay of the repeater E,via the grounded retardation coil 15, working contact and armature 3'7,resting contact and armature. 4L9, tip conductor 27 of the cord, trunkconductor 25, armature 19 andits working contact. The relay 15, uponoperatingcauses the operation ot'the reversing relay 16 which,.in a well:understood manner reverses the direction o'fcurrent flow back over thecalling line to ope ate metering, pay station or supervisory equipmentde endin u )011 the Joint from which the call originated.

In the description just given it will be re called that the operator hadher headsetautomatically connected to the incoming trunk when the callwas answered and that when she. extended the connection this equipmentwas automatically cut off. It is'desirable in certain instances for theoperator to come in on the connection to further supervise the call andin order to facilitate doing this an emergency key K is provided. Thiskey may be operated at any time. by the operator to cause theenergization of relay 40 to connect her equipment with the cord. It willbe under stood however that-this key is ordinarily used only in anemergency.

The connection having been established it will now be assumed that the.conversation has beencompleted andthe calling subscriber is the first torestore his receiver. Responsive to this act line relay '1? deenergizes,at its armature 14 opens conductor 26 of the trunk, which causes thedeenergization of relay 24 in the repeater E and of the supervisoryrelay 30 in the cord O, and at armature 10 breaks the. circuit of relay1-8 and momentarily closes a circuit for relay 22. The relay 18, upondeenergizing, removes ground from the holding conductor 13 to permit theswitches D and C to be released from theconnection so that they mayrestore to normal, and at its armature-19 switches the conductor fromthe winding of relay 15 to the Winding of slow release relay 23;Consequently the relay 15 and the reversing relay 16 controlled by itrestore to normal, While the relay 23 is held energized independent ofrelay 24 and, following the deenergization of relay 22, its circuithaving been broken at armature 21, applies ground to conductor 13, solong as the operators cord circuit 0 remains connected with theanswering and call- 1 111g acks, to make the trunk busy to selectorssuch as Inthecord O the deenergization of the relay at armature -41.causes disconnect lamp L to light up, and at armature 42 breaks thecircuit of relay 32 which in turn breaks the holding circuit ofrelay 35.Relay 32 upon restoring at its armature 34 also .completes a circuit forthe relay 4:0 frointhe grounded sleeve of the jack J, sleeve conducs torof the cord, resting contact and armature 34:, resting contact andarmature 58, and the winding of relay to battery. This relay thereforeresponds .to again connect the op erators set across the cord so. thatshe may ascertain the reason for the subscriber lat. substation B nothaving restored his receiver.

It the receiver is replaced at the'substation B before the subscriberreplaces his-receiverat substation A relay 68 Will restore removing theshort circuit. from relay 47. This relay will accordingly-be energizedand at its armature 18 light the supervisory lamp L to inform theoperator that the called subscriber has replaced his receiver.

1. In a telephone system, called lines, asource of current permanentlyconnected in bridge thereof, a cord circuit for answering incoming callsand for extending connections to said lines, a source of intermittent.ringing current for signalling said lines, a

relay responsive to the connection of the cord with a line to cause saidringing current source to be applied thereover without disconnectingsaid current. source in bridge of the called'line, and a relay placedunder control of the called subscriber, each time an interruption occursin the application of ring ing current to the called linefor disconnectsing said ringingcurrent.

i 2. I In a telephone system, a called line comprising tWo lineconductors terminating in a jack, a current source and aiirst relaypermanently connected in bridge oi? said c-onduc-' tors, a cord circuitfor ettectingconnections to said line, a source of intermittent ringingcurrent, a second relay responsive to the connection of said cord withsaid line for applying said ringing current thereover with outdisconnecting said first relay and said current source from across saidline conductors, means at said called line for actuating said firstrelay, and means operated by said first relay for disconnecting saidringing current.

'3. Inatelephone system, a called line comprising two line conductorsterminating in:

a jack, a current source and a first relay permanently connected inbridge of said conr If the subscriber o1 thezautoinartic exchangecurrent.

4. In a telephone system, a called line comprising two line conductorsterminating in a jack, a current source and a first relay permanentlyconnected in bridge of said conductors, a cord circuit for effectingconnections to said line, a source of intermittent ringing current, asecond relay responsive to the connec'tion of said cordwith said linefor applying said ringing current thereover without disconnectin saidfirst rela and said current source trom across said line conductors,means at said called line for actuating said first relay, and meansoperable by said first relay and efii'ective only during an interruptionin the application or said ringing current. for short circuiting saidsecond relay to discontinue the application of ringing current.

5. In a telephone system, calling and called lines, each comprising twoline, conductors terminating in a ack at an operators position, acurrent source and a first relay permanently connected in bridge of theline conductors of said called line, a cord circuit for establishingconnections between said lines, a source or intermittent ringingcurrent, a second relay in said cord for automatically connecting theoperators telephone to said calling line upon connecting thecordtherewith, a third relay in said cord for automaticallydisconnecting said operators telephone and for automatically connectingsaid source oi ringing current to said called line upon connecting saidcord therewith, Without disconnecting said first relay and said sourceof current from across said called line, means at said called line foractuating said first relay, and means operated by said first relay fordisconnecting said rin ing current. V

6. In a telephone system, calling and called lines, each comprising twoline conductors ;erminating in a jack at an operators position, a sourceof current and a first relay permanently connected in bridge of the lineconductors of said called line, a cord circuit for e."- tablishingconnections between said lines, a source of intermittent ringingcurrent, a second relay in said cord for automatically con necting theoperators telephone to said calling line upon connecting the cordtherewith,

a third relay in said cord for automatically disconnecting saidoperators telephone and for automatically connecting said source ofringing current to said called lineiupon con necting said cordtherewith, without discone necting said first relay and said source ofcurrent from said called line, means at said called line for actuatingsaid first relay, and means operable by said first relay and effectiveonly during an interruption in the application of said ringing currentfor disconnecting said ringing current.

7. In a telephone system, calling and called lines, each comprising twoline conductors terminating in a jack at'an operators posi-' tion, asource of current and first relay permanently connected in bridge of theline conductors of said called line, a cord circuit for establishingconnections between said lines, a source of intermittent ringingcurrent, a second relay in saidcord for automatically connecting theoperators telephone to said calling line upon connecting the cordtherewith, a third relay in said cord for automatically disconnectingsaid operators telephone and for automatically connecting said source ifringing current to said called line upon connecting aid'cord therewith,without disconnecting said first relayand said source of current fromsaid called line, means" at said called line for actuatingsaid firstrelay,'and means operable by said first relay andeffective only duringan interruption in the application "of said ringing current for shortcircuiting said'third relay to discontinue the application of saidringing current. V

8. Ina telephone system, calling and called lines, each comprising twoline conductors terminating in a jack at an operators position, a sourceof current and a first relay per manently connected in bridge of theline conductors of said called line, a cord circuit forestablishingconnections between said lines, a

source of intermittent ringing current, a second relay 1n sald cord forautomatically connecting. the operators telephone tosaid calling lineupon connecting the cord therewith, a third relay in said cord forautomatically disconnecting said operators telephoneand forautomatically connecting-said source of ringing current to said calledline; upon connecting said cord therewith, without disconnecting saidfirst relay and said source of cur I rent from said calledlin-e, meansat said called calling line for supervisory purposes upon thedisconnection of said ringing current.

9. Ina telephone system, a calling l1ne a two conductor trunkline'accessible thereto and terminating in a jack at an operatorsposition, a called line having two line conductors terminating in asecondjack at said position, a source of currentpermanently connected tosaid called line, a cord circuit for establishing connections betweensaid trunk line and said called line, means in said cord circuit forautomatically connecting the operators telephone to said trunk lineresponsive to connecting the cord therewith, a source of intermittentringing current, means in said cord circuit for automatically connectingsaid ringing current to said called line and for disconnecting saidoperators telephone responsive to connecting said cord with said calledline, without disconnecting said permanently connected current sourcefrom said called line, means controlled by said called line andincluding said permanently connected current source for disconnectingsaid ringing current, means for maintaining a current flow over saidtrunk line prior to the disconnection of said ringing current, and meansfor then altering the current flow over one conductor of said trunk linefor supervisory purposes. Y

10. In a telephone system, a callingline,

a two conductor trunk line accessible thereto and terminating in a jackat an operators position, a called line having two line conductorsterminating in a second jack at said called line, means controlled bysaid called.

line and including said permanently "connected current source fordisconnecting said ringing current, means for maintaining a current flowover said trunk line prior to the disconnection of said ringing current,means forthen altering the current flow over one conductor of said trunkline, and means res sponsivethereto for altering the current flow oversaid calling line for supervisory purposes. 1

11. In a telephone system, a calling line, a two conductor trunk lineaccessible thereto and terminating at an operatorsposition, a calledline, a cord circuit for establishing connections between said lines,means'in said cord circuit for maintaining a current flow over bothconductors of said trunk line after establishing connection therewith,but prior to the completion of a talking connection with said calledline, means in said cord circuit responsive after completion of saidtalking connection for altering the current flow over one conductor ofsaid trunk line, and means responsive thereto for altering the currentflow over said calling line.

In witness whereof, I hereunto subscribe my name this 21st day of March,A. D. 1927.

ROY r. GOULD.

